Published 19/10/2026 1 min readInvestment costs
How much does it cost to insulate a 120 m² house — a concrete example with numbers
How much does it cost to insulate a 120 m² house? A breakdown of the facade budget: mesh, adhesive, polystyrene, and render — with price ranges from basic to premium.
A 120 m² single-family home typically has about 130–150 m² of facade area. Let us calculate the costs for insulation (light-wet method).
140 m² facade budget
- EPS 100 polystyrene, 15 cm: £9–£14/m² → £1,260–£1,960
- Adhesive, mesh, anchors, primer: £5–£7/m² → £700–£980
- Silicone render + paint: £7–£12/m² → £980–£1,680
- Labor (scaffolding included): £18–£30/m² → £2,520–£4,200
- Flashings and corner finishes: £200–£500
Total: approx. £6,000–£9,400 (approx. £42–£66/m² of facade).
What increases the price
- Passive standard → thicker polystyrene (20 cm).
- Ventilated facade instead of light-wet (2–2.5× more expensive).
- Clamps and cornices — every decoration requires additional scaffolding and labor.
When does it pay off
With gas heating, a 25–35% saving amounts to £600–£1,200 annually → a return on investment in 6–10 years. Including the increase in property value — realistically 5–7 years.
Compare insulation quotes: post your job on LocalTrader with your square footage and polystyrene thickness.
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